This invention relates to mine clearing apparatus in the form of an attachment for mounting on the front of a vehicle and intended for clearing mines lying on the ground, close to the ground surface, or deep-laid mines.
The invention has been developed primarily in relation to a front mounted attachment for an armoured car, personnel carrier or tank, although it should be appreciated that the attachment may be mounted on any other suitable vehicle to be used for clearing mines.
In this specification, the reference to the "front" of a vehicle is intended to refer to the leading end of a vehicle with respect to its normal direction of travel. Thus, in some cases, this may be what would otherwise be regarded as the rear end of the vehicle.
One known apparatus of this type is disclosed in EP 0094901 and comprises a pair of plough blades which are mounted on a support frame fixed to the front of an armoured vehicle. The plough blades can be raised or lowered together, but when in the lowered, operative position any inclines of hummocks in the ground either cause the edge of the blade to dig deeper than is necessary, with consequent increase in draft force, or it may cause it to be higher than desirable, with the risk of not clearing any mines which may be present. This means that full use is not made of the available draft force of the vehicle. This type of apparatus also suffers from the disadvantage that there is a central space defined between the inboard ends of each plough blade, and this gives rise to an unploughed region between the blades, and which corresponds to the central region of the vehicle where the armour is usually thinnest, and particularly the vulnerable underside of the vehicle.
A further feature of the known apparatus is that the plough blades are only pivoted about a single axis, which extends perpendicular to the general path of travel of the vehicle, and there will be occasions in service, when the apparatus is operating over very uneven ground, but the blade is not able to position itself at an optimum position with respect to the ground surface and there is a substantial risk that a particular trough or depression in the ground surface may be uncleared by the plough as it travels over or at least partly through the upper surface of the ground, with resultant risk of exposure of the following vehicle to the action of an uncleared mine in the hollow. This problem could be attempted to be overcome by lowering the plough so as to dig deeper into the ground surface, but this will result in a very considerable increase in requirement for draft force which utilizes more power from the vehicle, and also slows down the clearing operation.
Given that the blades in the known apparatus are pivotable about a single axis, it is necessary to attach skids to the blades, in order to control the depth of the blades, and particularly the tines carried thereby, relative to the ground surface. The known apparatus is usually mounted on the front of a heavy AFV (armored fighting vehicle), and because of the difference in distance away from the pivot of the tines at the leading end of the blade, as compared with the distance of the tines at the rear end of the blade, raising the front tines by, say, one inch, causes the rear tines to be raised through a smaller distance, say three quarters of an inch. However, the depth of the tines, compared to the undulations commonly found and the relative differences in heights generally means that this is not too much of a problem for deep working tines.
However, for full width clearance of, for example, scatterable mines, where the blades extend transversely to cover the center of the path to be cleared, and the tines are not intended to extend so deeply into the ground surface, the undulations encountered may be generally the same, but the ratio of the distance of the tines at the leading end from the pivot to the distance of the rear tines from the pivot, compared to the reduced depth of clearance provided with lighter vehicles, makes the single pivot arrangement less attractive.
To enable the mine clearing apparatus to be lifted out of contact with the ground, when mine clearing is not required e.g. for normal travel of the vehicle to which the apparatus is attached, preferably a winch is mounted on the vehicle, and is connected by a hauling cable to any convenient hitch point on the apparatus, so as to pivot the entire apparatus upwardly about said first axis.
The present invention therefore seeks to overcome the limitations of the known apparatus by providing a pivot axis for the or each blade which extends approximately parallel to the intended direction of travel.